I. Field of the Invention
The present invention relates to vehicle refrigeration units, and more particularly to shrouds or other reinforced enclosures for protecting externally mounted vehicle refrigeration units from physical damage.
II. Prior Art
Vehicles which carry goods requiring refrigeration are often equipped with refrigeration units mounted to the top front of the trailer. These refrigeration units, sometimes referred to as “reefers” by those in the industry, benefit from their placement on the front of the vehicle, because the air flow that results during transportation serves to cool the refrigeration coils and condense the working fluid. While this particular location of the reefer provides advantageous refrigeration efficiencies, it is also the worse place for a reefer in terms of possible physical damage from low hanging tree limbs and the like.
Prior to the present invention, reefers mounted in this fashion were highly susceptible of damage. While such units are manufactured to commercial standards and operate trouble-free most of the time, they are not designed to withstand a heavy impact from a tree limb. Given the momentum of the vehicle and the stationary nature of the tree limb, the reefer often ends up absorbing much of the collision. Reefers are typically installed with a housing made of thin metal, plastic or fiberglass, but such housings are merely intended to protect the mechanical and electrical components from the elements. If a reefer is hit by a tree limb or low hanging object, the housing is often cracked or broken beyond repair, and the internal components are likewise damaged. With units of this type generally costing from $10,000 to $15,000, the replacement of a reefer unit is often an economically catastrophic event, especially for the small business owner whose services are highly dependent upon the reefer remaining intact. This situation is only exacerbated by the downtime for repair or replacement, and the possible loss of goods due to a failure to maintain the required temperature for perishable items.
Unfortunately, little has been done to address the foregoing problems. Many patents have issued for a variety of enclosures for such units, but all having the primary goal of improving the aerodynamic efficiency of the external design. For example, U.S. Pat. No. 4,310,192 to Fitzgerald discloses an aerodynamic wind deflector for a refrigerated trailer. This device appears effective for its stated purpose, and offers a hinged cover for accessing the reefer unit underneath the deflector. It also includes a grilled opening for the passage of air over the reefer unit. However, this device is preferably molded from fiberglass, which is simply not enough to protect against the damage explained above.
Similar devices are also illustrated in the following patents: U.S. Pat. No. 4,078,395 (Crowe); U.S. Pat. No. 4,468,060 (Fitzgerald); U.S. Pat. No. 4,567,734 (Dankowski); U.S. Pat. No. 5,388,424 (Chopko); U.S. Des. No. 258,233 (Taylor); and U.S. Des. No. 266,870 (Allard). Notably, none of these patents disclose the problems of tree limb and similar damage to reefer units. Moreover, none disclose or suggest a design of sufficient strength and rigidity which would minimize or eliminate such problems. Consequently, the present invention recognizes the nature and severity of the problem and directly provides a superior and innovative solution.